Abstract
Purpose:
Orbital floor fractures are caused by blunt trauma to the periocular area. We perform this reconstruction by inflating a silicon balloon that has been inserted into the maxillary sinus, and realigning bone fragments on the balloon. We call this procedure "Intra-Maxillary sinus Balloon Treatment" (IMBT). If the orbital floor is weak after balloon removal, the orbital contents may reinvaginate. In this study, we determined the strength of the orbital floor by visualizing the area using magnetic resonance imaging (MRI) after IMBT, and also observing it from the side of the maxillary sinus after balloon removal.
Methods:
The subjects were 3 patients with orbital floor defect. The surgical procedure involved approaching the fracture site from the skin below the lower eyelashes and incising the periosteum of the infraorbital margin. The orbital contents invaginating through the fracture site were then restored to their original state. After the oral mucosa in the canine fossa was incised, a 10-mm hole was made in the maxilla. A balloon was inserted into the maxillary sinus and inflated to prevent reinvagination of the orbital contents. On Postoperative Days 1 and 16, T1-weighted fat-suppressed gadolinium-enhanced MRI was performed in the coronal and sagittal planes of the orbit. After the balloon was removed on Postoperative Day 16, the orbital floor was observed from within the maxillary sinus with a rigid otoscope.
Results:
The maximum fracture area (mediolateral × anteroposterior diameter) was 15 × 20 mm, while the minimum was 10 × 15 mm. In all 3 patients, continuous membrane-like tissue with high signal intensity that did not exist on Postoperative Day 1 was observed between the orbit and the balloon on Postoperative Day 16. Observation of the orbital floor with a rigid otoscope confirmed that the fracture sites were covered by granulation tissue. Furthermore, the orbital floor was observed while the eyeball was pressed. Although loosening of the fracture site was observed in the patient with the largest fracture site, the orbital contents did not reinvaginate.
Conclusions:
MRI depiction of continuous granulation tissue in the fracture sites allowed us to assess the healing progress of the orbital floor. Furthermore, this study revealed that on the 16th day after IMBT, the orbital floor was strong enough to prevent reinvagination of the orbital contents without balloon support.
Keywords: 631 orbit •
742 trauma •
550 imaging/image analysis: clinical